Toy electronic musical instrument



United States Patent Inventors Norman Kramer Skokie; Burton C. Meyer,Chicago; Harry Disko, Park Ridge, 111. Appl. No. 801,305 Filed Feb. 24,1969 Patented Dec. 29, 1970 Assignee Marvin Glass & Associates Chicago,111. a partnership TOY ELECTRONIC MUSICAL INSTRUMENT 6 Claims, 5 DrawingFigs.

U.S. Cl 84/ 1.01, 84/1.28, 84/470 Int. Cl ..'G09b 15/ GlOh1/O0,Gl0h 5/04Field of Search 84/ 1 .01,

[56] References Cited UNITED STATES PATENTS 2,888,849 6/1959 Humphrey eta1. 84/1 .01 3,1 15,803 12/1963 Pedicano 84/470 3,376,778 4/1968 Musser84/483 3,460,425 8/1969 Kiepe 84/470 Primary ExaminerW. E. Ray

Attorney-James F. Coffee ABSTRACT: A toy musical instrument including anelectronic oscillator for producing musical tones through variation of aresistance in the circuit. The variable resistance comprises an area ofpencil lead or graphite deposited on a paper sheet, which is contactedby a graphite pencil also connected in the circuit to produce a musicalsound. The position of the pencil point along the length of the graphitearea determines the amount of resistance in the oscillator circuit and,consequently, the frequency of the sound produced. The paper sheet ispreferably marked to indicate the sequence of positions for the pencilpoint to produce a particular melody.

PATENTEU m2 9 I976 ATT NEY TOY ELECTRONIC MUSICAL INSTRUMENT BACKGROUNDOF THE INVENTION The present invention relates to a toy musicalinstrument and is particularly directed to an electronic instrumentwherein the user participates in the conditioning of the instrument sothat almost an infinite variety of musical tones can be reproduced.

Toy musical instruments have long been popular with children and thepresent invention is particularly directed to a toy instrument having amode of operation which is somewhat magical in nature and, therefore,particularly appealing to the child.

It is a primary object of the present invention to provide a toy musicalinstrument, which is capable of playing musical tones over a wide rangethrough the establishment of contact between a graphite pencil and anarea of graphite deposited on a sheet of paper. A more detailed objectof the invention is to provide a toy musical instrument including anoscillator circuit connected with a speaker and including a variableresistance in the form of deposited particles of graphite, whereinmusical tones are produced by contacting an ordinary pencil, which isconnected in the circuit, with the deposited graphite. Other objectswill be apparent from the following description of the selectedembodiment of the invention, as illustrated in the accompanyingdrawings, wherein: 7

FIG. 1 is a perspective view of the toy musical instrument and itsrelated components;

FIG. 2 is a sectional view taken along the line 2-2 in FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 1;

FIG. 4 is an enlarged sectional view taken along the line 4-4 in FIG.1;and

FIG. 5 is a schematic wiring diagram of the electronic circuit used inthe toy.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference particularly toFIG. 1 of the drawings, it will be seen that the selected embodiment ofthe invention comprises a generally rectangular frame or housing 10,preferably of plastic, including an inclined upper surface portion 12for removably receiving sheets of paper 14, a pencil holder 16 connectedby a lead wire 18 to an electronic circuit disposed within a closedsection of the housing 10, and a speaker 20 within the housing which isalso connected with the electronic circuit.

A sheet of paper or the like is coated throughout a predetermined area22 with graphite particles, as by rubbing an ordinary black lead pencil24 back and forth across such area, and the paper sheet is then placedon the inclined top 12 with one end of the graphite coated area 22 incontact with a metal contact element 26 forming a portion of theelectronic circuit. The electronic circuit is essentially an oscillator,and the circuit is closed by placing the tip of the lead pencil 24 inengagement with any selected portion of the graphite area 22. Thegraphite area serves as an external resistance in the circuit and, ofcourse, the amount of resistance introduced into the circuit isdependent upon the size of the graphite area extending between the pointof pencil contact and the metal clip 26. Variation in this externalresistance will result in variation of the tone produced by theoscillator through the speaker.

The range of sounds or notes produced with the described structure canbe fairly well determined by the size of the graphite area 22 andthickness of the deposit in such area. Furthermore, by providing apredetermined area of deposit of graphite a fairly accurate musicalscale can be reproduced, as indicated on the paper sheets in FIG. 1.Each of the dots 28 in such sheet represent a particular note andsignify that, in order to reproduce such note, the pencil 24 shouldcontact the graphite area 22 at that point along its length. Particularmelodies can be illustrated for easy following by the child byindicating on the sheet 14 the sequence of the positions to be contactedby the graphite or lead pencil.

It is contemplated that the toy instrument described herein will includea plurality of printed sheets 14, each having sequentially arrangedmarkings 28 to provide for reproduction of a particular song, and thechild will complete the sheet for use in the toy by rubbing a pencilacross the indicated area 22, which is initially blank, until there is acomplete deposit of graphite on the paper. Preferably, the graphiteshould be deposited uniformly and to an extent such that there is a highgloss appearance of the graphite. In order to accurately guide the childin the placement of graphite on the sheet. there is also provided atemplate 30 which may be ofplastic and which includes a wedge-shaped ortrapezoidal opening 32 cor responding with the desired shape of the areaof graphite. An ordinary pencil is useable with the toy instrument, withthe best results being obtained with a soft pencil, such as a No. 2 orone having even softer lead. The end of the pencil should be without aneraser tip, since it is necessary that as the pencil is placed in theholder 16 the lead must contact the metal clip portion of the holder. Asseen particularly in FIG. 4, the pencil holder 16 is a generallycylindrical part having a metal clip 34 at its inner end, which isconnected by a wire 18 with the electrical circuit in housing 10 andwhich also includes a free end portion-38 in position for engagementwith the lead in the center of the pencil.

The electrical circuit is essentially an oscillator and in theillustrated embodiment (FIG. 5) includes a transistor 40, threecapacitors, C C and C a speaker 20, and a battery 50. The selectedembodiment is adapted to be powered by a 9 volt transistor radio batteryand the transistor 40 is of the NPN type. However, PNP types work justas well with appropriate changes in component polarities. Capacitor C isdisposed across the battery in the circuit and serves to stabilize thevoltage and thereby sustain the musical note being played by sustainingthe frequency rate at the speaker 20. Capacitor C serves primarily toadjust the waveform 'of the oscillator to provide a more pleasantmusical sound. The speaker used in the illustrated embodiment has acenter-tapped speaker voice coil. Essentially the circuit provides anoscillation only when the external resistance Rx, i.e. graphite area 22,is introduced into the circuit. The frequency of oscillation, andconsequently the musical tone, is determined solely by the amount ofexternal resistance which in turn is determined by the position of thepencil 24 on the graphite area 22.

As seen in FIG. 5, there is another resistance R in the circuit, butthis is primarily a safety feature to prevent drain of the battery whenthe toy is not in use. The resistance R is relatively small butsufficient to effect an audible sound from the speaker 20 in the eventthat the pencil contacts the exposed metal clip 26. Consequently, if achild should lay the pencil down and it contacts the clip there will bean audible sound to warn the child to remove the pencil. In thisrespect, there is preferably provided a recess 52 in the frame 10 forholding the pencil 24 and its holder 16 when not in use.

It will, of course, be apparent that the oscillator may take other formsand include other components and that the speaker may be another form ofdynamic speaker, such as a lower impedance noncenter/tapped type with acenter tapped primary type of output transformer. The describedcircuitry is an example of a relatively simple circuit which is useableeffectively with the external resistance provided by the pencil orgraphite deposited area to produce a great variety of musical tones.Very satisfactory results have been achieved with the use of theillustrated circuitry, wherein C is a 0.47 MFD 10 volt mylar capacitor,C is a 25 MFD 10 volt electrolytic capacitor, C is a 0.0022 MFD ceramicdisc capacitor, and the speaker 48 is a 2% inch diameter 50 ohmcenter-tapped speaker.

It is particularly noteworthy that with the described device a musicaltone is produced as long as the pencil contacts the graphite area.Further, such tone is changed by simply shifting the pencil whileretaining contact with the graphite area and consequently some veryinteresting effects can be achieved. For example, by rapidly moving thepencil back and forth along a length of the graphite area there isproduced a tremolo effect.

As indicated previously, the range of musical tones produced with thedevice is dependent upon the range of the external resistance Rx. Arange of eight notes with all of the intermediate tones is easilyproduced by providing a wedgeshaped area 22 of approximately 6 inches inlength which varies from a height or width of about one-fourth inch atthe outer end to a width of approximately 1 /2 inches at the point ofcontact with the metal clip. The described area 22 provides afairlyuniform spacing of the notes in an octave, while also providing acomfortable spacing between the octave and the contact 26. Of course,such spacing will also provide musical tones if desired. It will also beobvious that the area of graphite can be almost any shape and length,but the spacing of the musical notes produced will vary widely andnonuniformly with such other shapes.

Although shown and described with respect to particular apparatus andcircuitry, it will be apparent that modifications might be made withoutdeparting from the principles of this invention.

We claim:

I. A toy musical instrument comprising electronic means for generatingdifferent musical tones of the scale and including a speaker, anoscillator circuit connected with said speaker, and an externalresistance for increment control of the oscillating frequency to producevariation in the tone generated through said speaker.

2. A toy musical instrument as set forth in claim 1, wherein 3. A toymusical instrument as set forth in claim 2 wherein H said probe is agraphite pencil.

I u u W 4. A toy musical instrument including electronic means forgenerating different musical tones and comprising, a speaker, anoscillator circuit connected with said speaker and with a variableexternal resistance, said variable resistance comprising an area ofdeposited graphite which is connectable in parallel with said oscillatorcircuitby contact thereof by a conductive probe which is also connectedwith said oscillator circuit, whereby the amount of resistance and theresulting tone generated by said speaker is determined by the positionof said probe in said graphite area. i

5. A toy musical instrument as set forth in claim 4, wherein saidconductive probe is in the form of a lead pencil having connection atone end with said circuit and having its other end adapted to form saidgraphite area through moving con tact with a sheet of material adaptedto receive the graphite.

6. A toy musical instrument as set forth in claim 4, including a sheetof material having said area of deposited graphite thereon and havingindicia signifying different musical notes of a melody and arranged insequence, so that the melody can be reproduced by sequential placementof said probe on said graphite area at the places indicated.

